1-Substituted phenyl-pyridazone herbicides

ABSTRACT

Substituted pyridazone derivatives having a good herbicidal action, herbicides containing these compounds as active ingredients, and a process for controlling the growth of unwanted plants with these compounds.

This is a continuation of application Ser. No. 194,439 filed Oct. 6, 1980, abandoned, which is a continuation of Ser. No. 007,006 filed Jan. 26, 1979, abandoned.

The present invention relates to new and valuable pyridazones, herbicides containing these compounds as active ingredients, and a process for controlling the growth of unwanted plants with these compounds.

It has been disclosed to use 1-phenyl-4,5-dimethoxypyridazone-(6), 1-(m-trifluoromethylphenyl)-4,5-dimethoxypyridazone-(6) and 1-(m-tetrafluoroethoxyphenyl)-4-methylamino-5-chloropyridazone-(6) as herbicides (German Laid-Open Application DE-OS No. 2,526,643, Belgian 728,164, and German No. 1,197,676).

We have now found that substituted pyridazones of the formula ##STR1## where R and R¹ denote lower alkoxy, preferably methoxy, R² denotes difluoromethyl, fluoro, chloro, or X--R⁴, X denoting O or S and R⁴ denoting haloalkyl of 1 to 3 carbon atoms, e.g., --CHF₂, --CF₂ --CHF₂, --CF₂ CHF--CF₃, --CF₂ --CHFCl, --CF₂ --CHFBr or CF₃, and R³ denotes hydrogen when R² is difluoromethyl or X--R⁴, or fluoro when R² is fluoro or chloro, have a good herbicidal action.

The new compounds may be prepared by reacting 4,5-dihalo- or 4-alkoxy-5-halopyridazones of the formula ##STR2## where A denotes halogen (Cl, Br) or alkoxy (methoxy) and Hal denotes halogen (Cl, Br) and R² and R³ have the above meanings, with an alcoholate of the formula R--R or R¹ --B, R and R¹ having the above meanings and B denoting Na or K, in the presence of an organic liquid.

The 4-alkoxy-5-halopyridazones and 4,5-dihalopyridazones required as starting products are either known or can be obtained in analogy to the processes disclosed in German No. 1,245,207, German No. 1,210,241 and German Laid-Open Application DE-OS No. 2,526,643; for instance, substituted hydrazines are prepared in conventional manner by reduction from the corresponding diazonium salt and are reacted, with or without being isolated as salts, with a 3-formyl-2,3-dihaloacrylic acid in known manner to give the corresponding pyridazone.

Purer products are obtained when the substituted hydrazines are isolated as salts, e.g., hydrochlorides, before the reaction to give the corresponding pyridazone.

When the 4,5-dialkoxypyridazones are prepared by reaction with an alcoholate, there are used for example 2 moles of alcoholate per mole of pyridazone when 4,5-dihalopyridazones are employed, and for example 1 mole of alcohoalte per mole of pyridazone when 4-alkoxy-5-halopyridazones are employed.

Suitable organic solvents are those which are inert to alcoholates between 100° and 160° C., e.g., toluene or xylene. The reaction may be carried out at from 100° to 160° C.

The intermediates have the following physical data:

    ______________________________________                                          ##STR3##                                                                      R.sup.5                                                                              R.sup.6 R.sup.2         R.sup.3                                                                            m.p. (°C.)                            ______________________________________                                         Cl    Cl      F               F   196-197                                      Cl    Cl      CHF.sub.2       H   118-119                                      Br    Br      OCF.sub.2CHFCF.sub.3                                                                           H   72-74                                        Cl    Cl      Cl              F   200-202                                      CH.sub.3 O                                                                           Cl      SCF.sub.3       H   129-131                                      Cl    Cl      OCF.sub.2CHF.sub.2                                                                             H   74-75                                        Cl    Cl      OCHF.sub.2      H   143-144                                      Br    Br      OCF.sub.2CHFCl  H   72-74                                        Br    Br      OCF.sub.3       H   86-88                                        Cl    Cl      OCF.sub.2CHFBr  H   67-68                                        ______________________________________                                    

EXAMPLE 1

7.2 parts (by weight) of 30% (by weight) sodium methylate solution is concentrated to dryness in vacuo and the residue is slurried in 250 parts of toluene. 10.8 parts of 1-(3-trifluoromethylthiophenyl)-4-methoxy-5-chloropyridazone-6 is added and the suspension is refluxed for 2 hours. After filtration has been carried out, the toluene is evaporated in vacuo. The residue is recrystallized from isopropanol. There is obtained 5.9 parts of 1-(3-trifluoromethylthiophenyl)-4,5-dimethoxypyridazone-6; m.p.: 93°-95° C.

EXAMPLE 2

39.6 parts of 30% sodium methylate solution is evaporated to dryness in vacuo and the residue is slurried in 500 parts of toluene. 36.6 parts of 1-(3-difluoromethoxyphenyl)-4,5-dichloropyridazone-6 is added and the whole refluxed for 2 hours. After filtration has been carried out, the toluene is evaporated in vacuo.

Yield: 28 parts of 1-(3-difluoromethoxyphenyl)-4,5-dimethoxypyridazone-6.

Melting point: 48°-50° C., after chromatography on SiO₂ using a 7:3 mixture of toluene and acetone.

The following compounds are obtained analogously:

    ______________________________________                                          ##STR4##                                                                                                         m.p.                                        R     R.sup.1 R.sup.2          R.sup.3                                                                            (°C.)                                                                          n.sub.D.sup.23                       ______________________________________                                         CH.sub.3 O                                                                           CH.sub.3 O                                                                             F                F   136-138                                     CH.sub.3 O                                                                           CH.sub.3 O                                                                             OCF.sub.2CHF.sub.2                                                                              H    81-83                                      CH.sub.3 O                                                                           CH.sub.3 O                                                                             CHF.sub.2        H    52-55                                      CH.sub.3 O                                                                           CH.sub.3 O                                                                             OCF.sub.2CHFCF.sub.3                                                                            H    58-60                                      CH.sub.3 O                                                                           CH.sub.3 O                                                                             Cl               F   148-149                                     CH.sub.3 O                                                                           CH.sub.3 O                                                                             OCF.sub.3        H    84-85                                      CH.sub.3 O                                                                           CH.sub.3 O                                                                             OCF.sub.2CHFCl   H    64-65                                      C.sub.2 H.sub.5 O                                                                    C.sub.2 H.sub.5 O                                                                      OCF.sub.2CHF.sub.2                                                                              H   1.5177                                      CH.sub.3 O                                                                           CH.sub.3 O                                                                             OCF.sub.2CHFBr   H    68-69                                      ______________________________________                                    

Application may be effected for instance in the form of directly sprayable solutions, powders, suspensions (including high-percentage aqueous, oily or other suspensions), dispersions, emulsions, oil dispersions, pastes, dusts, broadcasting agents, or granules by spraying, atomizing, dusting, broadcasting or tering. The forms of application depend entirely on the purpose for which the agents are being used; in any case they should ensure a fine distribution of the active ingredient.

For the preparation of solutions, emulsions, pastes and oil dispersions to be sprayed direct, mineral oil fractions of medium to high boiling point, such as kerosene or diesel oil, further coal-tar oils, and oils of vegetable or animal origin, aliphatic, cyclic and aromatic hydrocarbons such as benzene, toluene, xylene, paraffin, tetrahydronaphthalene, alkylated naphthalenes and their derivatives such as methanol, ethanol, propanol, butanol, chloroform, carbon tetrachloride, cyclohexanol, cyclohexanone, chlorobenzene, isophorone, etc., and strongly polar solvents such as dimethylformamide, dimethylsulfoxide, N-methylpyrrolidone, water, etc. are suitable.

Aqueous formulations may be prepared from emulsion concentrates, pastes, oil dispersions or wettable powders by adding water. To prepare emulsions, pastes and oil dispersions the ingredients as such or dissolved in an oil or solvent may be homogenized in water by means of wetting or dispersing agents, adherents or emulsifiers. Concentrates which are suitable for dilution with water may be prepared from active ingredient, wetting agent, adherent, emulsifying or dispersing agent and possibly solvent or oil.

Examples of surfactants are: alkali metal, alkaline earth metal and ammonium salts of ligninsulfonic acid, naphthalenesulfonic acids, phenolsulfonic acids, alkylaryl sulfonates, alkyl sulfates, and alkyl sulfonates, alkali metal and alkaline earth metal salts of dibutylnaphthalenesulfonic acid, lauryl ether sulfate, fatty alcohol sulfates, alkali metal and alkaline earth metal salts of fatty acids, salts of sulfated hexadecanols, heptadecanols, and octadecanols, salts of sulfated fatty alcohol glycol ethers, condensation products of sulfonated naphthalene and naphthalene derivatives with formaldehyde, condensation products of naphthalene or naphthalenesulfonic acids with phenol and formaldehyde, polyoxyethylene octylphenol ethers, ethoxylated isooctylphenol, ethoxylated octylphenol and ethoxylated nonylphenol, alkylphenol polyglycol ethers, tributylphenyl polyglycol ethers, alkylaryl polyether alcohols, isotridecyl alcohol, fatty alcohol ethylene oxide condensates, ethoxylated castor oil, polyoxyethylene alkyl ethers, ethoxylated polyoxypropylene, lauryl alcohol polyglycol ether acetal, sorbitol esters, lignin, sulfite waste liquors and methyl cellulose.

Powders, dusts and broadcasting agents may be prepared by mixing or grinding the active ingredients with a solid carrier.

Granules, e.g., coated, impregnated or homogeneous granules, may be prepared by bonding the active ingredients to solid carriers. Examples of solid carriers are mineral earths such as silicic acid, silica gels, silicates, talc, kaolin, Attaclay, limestone, talc, chalk, bole, loess, clay, dolomite, diatomaceous earth, calcium sulfate, magnesium sulfate, magnesium oxide, ground plastics, fertilizers such as ammonium sulfate, ammonium phosphate, ammonium nitrate, and ureas, and vegetable products such as grain flours, bark meal, wood meal, and nutshell meal, cellulosic powders, etc.

The formulations contain from 0.1 to 95, and preferably 0.5 to 90, % by weight of active ingredient.

The new herbicidal pyridazones according to the invention may be mixed and applied with numerous representatives of other herbicidal or growth-regulating active ingredient groups. Examples of suitable mixture components are anilides, diazines, benzothiadiazinones, 2,6-dinitroanilines, N-phenylcarbamates, biscarbamates, thiolcarbamates, halocarboxylic acids, triazines, amides, ureas, diphenyl ethers, triazinones, uracils, benzofuran derivatives, etc. Such combinations broaden the spectrum of action, and synergistic effects are at times achieved. A number of active ingredients which together with the new compounds give mixtures useful for various application are as are listed below by way of example.

    ______________________________________                                          ##STR5##                                                                      R                R.sup.1   R.sup.2                                             ______________________________________                                          ##STR6##        NH.sub.2  Cl                                                   ##STR7##        NH.sub.2  Br                                                   ##STR8##        NH.sub.2  Cl                                                   ##STR9##                                                                                        ##STR10##                                                                               Cl                                                   ##STR11##       NHCH.sub.3                                                                               Cl                                                   ##STR12##       NHCH.sub.3                                                                               Cl                                                   ##STR13##                                                                                       ##STR14##                                                                               Cl                                                  ______________________________________                                          ##STR15##                                                                     R            R.sup.1 R.sup. 2                                                                               R.sup.3                                           ______________________________________                                         H            i-C.sub.3 H.sub.7                                                                      H       H     or salts of this                                                               compound                                    H            i-C.sub.3 H.sub.7                                                                      H       CH.sub.3                                                                             or salts of this                                                               compound                                    CH.sub.2OCH.sub.3                                                                           i-C.sub.3 H.sub.7                                                                      H       H                                                  ##STR16##               or salts of this compound                             ______________________________________                                          ##STR17##                                                                     R     R.sup.1   R.sup.2 R.sup.3     R.sup.4                                    ______________________________________                                         H     F.sub.3 C H       C.sub.2 H.sub.5                                                                            C.sub.4 H.sub.9                            H     F.sub.3 C H       n-C.sub.3 H.sub.7                                                                          n-C.sub.3 H.sub.7                          H     F.sub.3 C H       CH.sub.2CH.sub.2 Cl                                                                        n-C.sub.3 H.sub.7                          H     SO.sub.2 NH.sub.2                                                                        H       n-C.sub.3 H.sub.7                                                                          n-C.sub.3 H.sub.7                          H     F.sub.3 C H       n-C.sub.3 H.sub.7                                                                           ##STR18##                                 H.sub.3 C                                                                            H.sub.3 C H       H           CH(C.sub.2 H.sub.5).sub.2                  H     F.sub.3 C NH.sub.2                                                                               n-C.sub.3 H.sub.7                                                                          n-C.sub.3 H.sub.7                          H     H.sub.3 C H       n-C.sub.3 H.sub.7                                                                          n-C.sub.3 H.sub.7                          ______________________________________                                          ##STR19##                                                                     R          R.sup.1  R.sup.2                                                    ______________________________________                                          ##STR20## H        i-C.sub.3 H.sub.7                                           ##STR21## H        CH(CH.sub.3)CCH                                             ##STR22## H        CH.sub.2CCCH.sub.2 Cl                                       ##STR23## H        i-C.sub.3 H.sub.7                                           ##STR24## H        CH(CH.sub.3)CONHC.sub.2 H.sub.5                             ##STR25## H        NC(CH.sub.3).sub.2                                         ______________________________________                                          ##STR26##                                                                     R                 R.sup.1     R.sup.2                                          ______________________________________                                          ##STR27##        H           CH.sub.3                                          ##STR28##        H           C.sub.2 H.sub.5                                   ##STR29##        CH.sub.3    CH.sub.3                                          ##STR30##        H           C.sub.2 H.sub.5                                   ##STR31##        H           C.sub.2 H.sub.5                                  ______________________________________                                          ##STR32##                                                                     R          R.sup.1    R.sup.2                                                  ______________________________________                                         i-C.sub.3 H.sub.7                                                                         i-C.sub.3 H.sub.7                                                                         CH.sub.2CClCCl.sub.2                                     i-C.sub.3 H.sub.7                                                                         i-C.sub.3 H.sub.7                                                                         CH.sub.2CClCHCl                                          n-C.sub.3 H.sub.7                                                                         n-C.sub.3 H.sub.7                                                                         C.sub.2 H.sub.5                                           ##STR33## C.sub.2 H.sub.5                                                                           C.sub.2 H.sub.5                                          sec.-C.sub.4 H.sub.9                                                                      sec.-C.sub.4 H.sub.9                                                                      C.sub.2 H.sub.5                                          n-C.sub.3 H.sub.7                                                                         n-C.sub.3 H.sub.7                                                                         n-C.sub.3 H.sub.7                                        i-C.sub.4 H.sub.9                                                                         i-C.sub.4 H.sub.9                                                                         C.sub.2 H.sub.5                                           ##STR34## C.sub.2 H.sub.5                                                                           C.sub.2 H.sub.5                                          i-C.sub.3 H.sub.7                                                                         i-C.sub.3 H.sub.7                                                                          ##STR35##                                               i-C.sub.3 H.sub.7                                                                         i-C.sub.3 H.sub.7                                                                          ##STR36##                                               ______________________________________                                          ##STR37##                                                                     ______________________________________                                         CH.sub.2CClCHCl                                                                CH.sub.2CClCCl.sub.2                                                           ______________________________________                                          ##STR38##                                                                     R                 X      Y     R.sup.1                                         ______________________________________                                         CH.sub.3          Cl    Cl     Na                                               ##STR39##        Cl    H      CH.sub.3                                         ##STR40##        H     H      H, or salts of this compound                    Cl                Cl    Cl     Na                                               ##STR41##        H     CH.sub.3                                                                              CH.sub.3                                         ##STR42##        H     CH.sub.3                                                                              C.sub.2 H.sub.5                                 C.sub.2 H.sub.5   Cl    Cl     Na                                               ##STR43##        H     CH.sub.3                                                                              i-C.sub.3 H.sub.7                                ##STR44##        H     CH.sub.3                                                                              CH.sub.3                                         ##STR45##        H     CH.sub.3                                                                              CH.sub.2CH(CH.sub.3).sub.2                       ##STR46##        H     CH.sub.3                                                                              Na                                               ##STR47##        H     CH.sub.3                                                                              CH.sub.3                                        ______________________________________                                          ##STR48##                                                                     R    R.sup.1   R.sup.2 R.sup.3         X                                       ______________________________________                                         H    tert.-C.sub.4 H.sub.9                                                                    H       C.sub.2 H.sub.5 SCH.sub.3                               H    i-C.sub.3 H.sub.7                                                                        H       i-C.sub.3 H.sub.7                                                                              SCH.sub.3                               H    i-C.sub.3 H.sub.7                                                                        H       C.sub.2 H.sub.5 SCH.sub.3                               H    CH.sub.3  H       i-C.sub.3 H.sub.7                                                                              SCH.sub.3                               H    i-C.sub.3 H.sub.7                                                                        H       C.sub.2 H.sub.5 Cl                                      H    i-C.sub.3 H.sub.7                                                                        H                                                                                       ##STR49##      Cl                                      H    C.sub.2 H.sub.5                                                                          H       C.sub.2 H.sub.5 Cl                                      H    C.sub.2 H.sub.5                                                                          H                                                                                       ##STR50##      Cl                                      H    i-C.sub.3 H.sub.7                                                                        H       i-C.sub.3 H.sub.7                                                                              Cl                                      H    i-C.sub.3 H.sub.7                                                                        H       i-C.sub.3 H.sub.7                                                                              OCH.sub.3                                     ##STR51##                                                                               H                                                                                       ##STR52##      Cl                                      H    C.sub.2 H.sub.5                                                                          H       CH(CH.sub.3)CH.sub.2OCH.sub.3                                                                  Cl                                      H    C.sub.2 H.sub.5                                                                          H       CH(CH.sub.3)CCH Cl                                      ______________________________________                                          ##STR53##                                                                     R                R.sup.1 R.sup.2                                               ______________________________________                                         CH.sub.3         CH.sub.3                                                                               CH(C.sub.6 H.sub.5).sub.2                              ##STR54##       H                                                                                       ##STR55##                                            C.sub.2 H.sub.5  C.sub.2 H.sub.5                                                                         ##STR56##                                            HCCC(CH.sub.3).sub.2                                                                            H                                                                                       ##STR57##                                             ##STR58##       H       CH.sub.3                                              ______________________________________                                          ##STR59##                                                                     R                R.sup.1                                                                               R.sup.2                                                                               R.sup.3                                         ______________________________________                                          ##STR60##       H      CH.sub.3                                                                              CH.sub.3                                         ##STR61##       H      CH.sub.3                                                                              H                                                ##STR62##       H      CH.sub.3                                                                              CH.sub.3                                         ##STR63##       H      CH.sub.3                                                                              CH.sub.3                                         ##STR64##       H      CH.sub.3                                                                              OCH.sub.3                                        ##STR65##       H      CH.sub.3                                                                              OCH.sub.3                                        ##STR66##       H      CH.sub.3                                                                              OCH.sub.3                                        ##STR67##       H      CH.sub.3                                                                              OCH.sub.3                                        ##STR68##       H      CH.sub.3                                                                              CH.sub.3                                         ##STR69##          H      CH.sub.2CH(CH.sub.3).sub.2                           ##STR70##       CH.sub.3                                                                              H      CH.sub.3                                         ##STR71##       H      CH.sub.3                                                                              CH.sub.3                                         ##STR72##       H      H                                                                                      ##STR73##                                      ______________________________________                                          ##STR74##                                                                     R         R.sup.1  R.sup.2 R.sup.3                                             ______________________________________                                         NO.sub.2  CF.sub.3 H       H                                                   Cl        CF.sub.3 H       COOH, or salts or esters                                                       of this compound                                    Cl        Cl       H                                                                                       ##STR75##                                          H         CF.sub.3 Cl      OC.sub.2 H.sub.5                                    ______________________________________                                          ##STR76##                                                                     R             R.sup.1          R.sup.2                                         ______________________________________                                         tert.-C.sub.4 H.sub.9                                                                        NH.sub.2         SCH.sub.3                                        ##STR77##    NH.sub.2         CH.sub.3                                        tert.-C.sub.4 H.sub.9                                                                         ##STR78##       SCH.sub.3                                       ______________________________________                                          ##STR79##                                                                     R      R.sup.1       R.sup.2   R.sup.3                                         ______________________________________                                         H      CH.sub.3      Br                                                                                        ##STR80##                                      H      CH.sub.3      Cl        tert.-C.sub.4 H.sub.9                           H      CH.sub.3      Cl                                                                                        ##STR81##                                      H      (CH.sub.2).sub.3                                                                                    ##STR82##                                          H      CH.sub.3      Br        C.sub.3 H.sub.7 i                               ______________________________________                                          ##STR83##                                                                            R       R.sup.1                                                         ______________________________________                                                CH.sub.3                                                                               C.sub.2 H.sub.5                                                         ##STR84##                                                                             C.sub.2 H.sub.5                                                         ##STR85##                                                                             C.sub.2 H.sub.5                                                 ______________________________________                                          ##STR86##                                                                      ##STR87##                                                                       #STR88##                                                                      ##STR89##                                                                     R     R.sup.1      R.sup.2       R.sup.3                                       ______________________________________                                         H     n-C.sub.3 H.sub.7                                                                           CH.sub.2CHCH.sub.2                                                                           CH.sub.3                                      Na    n-C.sub.3 H.sub.7                                                                           CH.sub.2CHCH.sub.2                                                                           CH.sub.3                                      ______________________________________                                          ##STR90##               or salts or esters of this compound                    ##STR91##                                                                      ##STR92##                                                                      ##STR93##                                                                      ##STR94##                                                                      ##STR95##               or salts, esters or amides of this compound            ##STR96##               or salts, esters or amides of this compound            ##STR97##               or salts, esters or amides of this compound            ##STR98##                                                                      ##STR99##                                                                      ##STR100##              or salts of this compound                              ##STR101##                                                                     ##STR102##              or salts of this compound                             ______________________________________                                          ##STR103##                                                                    R.sup.1       R.sup.2 R.sup.3                                                  ______________________________________                                          ##STR104##   H       H     salts, esters, amides                               ##STR105##   CH.sub.3                                                                               H     "                                                   ##STR106##   H       H     "                                                   ##STR107##   CH.sub.3                                                                               H     "                                                   ##STR108##   H       H     "                                                   ##STR109##   CH.sub.3                                                                               H     "                                                  ______________________________________                                          ##STR110##                                                                    R.sup.1      R.sup.2     R.sup.3                                               ______________________________________                                          ##STR111##  sec.C.sub.4 H.sub.9                                                                        H                                                      ##STR112##  tert.C.sub.4 H.sub.9                                                                       H                                                      ##STR113##  tert.C.sub.4 H.sub.9                                                                       CH.sub.3                                              H            CH.sub.3    H salts and esters                                    H            sec.C.sub.4 H.sub.9                                                                        H salts and esters                                    H            tert.C.sub.4 H.sub.9                                                                       H salts and esters                                    H            tert.C.sub.4 H.sub.9                                                                       CH.sub.3 salts and esters                             ______________________________________                                          ##STR114##                                                                    R.sup.1     R.sup.2        R.sup.3                                             ______________________________________                                          ##STR115##                                                                                 ##STR116##    CH.sub.2 Cl                                          ##STR117##                                                                                 ##STR118##    CH.sub.2 Cl                                          ##STR119## CH.sub.2CH.sub.2 OCH.sub.3                                                                    CH.sub.2 Cl                                          ##STR120## CH.sub.2OCH.sub.3                                                                             CH.sub.2 Cl                                          ##STR121##                                                                                 ##STR122##    CH.sub.2 Cl                                          ##STR123## CH.sub.2OC.sub.4 H.sub.9 n                                                                    CH.sub.2 Cl                                          ##STR124##                                                                                 ##STR125##    CH.sub.2 Cl                                          ##STR126## H                                                                                              ##STR127##                                          ##STR128## H              C.sub.2 H.sub.5                                      ##STR129## H              C(CH.sub.3).sub.2C.sub.3 H.sub.7                     ##STR130## H              CH.sub.3                                            ______________________________________                                          ##STR131##                                                                    X            X.sub.1   R                                                       ______________________________________                                         Br           Br        H and salts                                             I            I         H and salts                                             Br           Br                                                                                        ##STR132##                                             ______________________________________                                          ##STR133##                and salts                                           X = NO.sub.2                                                                   CN                                                                              ##STR134##                salts and esters                                     ##STR135##                                                                     ##STR136##                                                                     ##STR137##                                                                    ______________________________________                                    

EXAMPLE 3 Herbicidal action of the new compounds

The following experiments demonstrate the influence of various compounds according to the invention on the germination and growth of unwanted and crop plants. The series of experiments were carried out in the greenhouse and in the open.

I. Greenhouse exeriments

Plastic flowerpots having a volume of 300 cm³ were filled with a loamy sand containing about 1.5% humus. Seeds of the test plants given in Table 1 were sown shallow, and separated according to species. In the preemergence treatment, the active ingredients were then applied immediately to the surface of the soil. The active ingredients were suspended or emulsified in water as the vehicle and sprayed onto the surface of the soil by means of atomizing nozzles. After treatment, the vessels were lightly sprinkler-irrigated to stimulate germination and growth, and to activate the chemical compounds. The vessels were then covered with transparent plastic hoods until the plants had taken root. This cover ensured uniform germination of the test plants, to the extent that this was not impaired by the active ingredient.

For the postemergence treatment, the plants were first grown to a height of from 3 to 10 cm, depending on habit, before being treated. No hoods were placed on the pots. The plants were placed in either cooler (15°-30° C.) or warmer (25°-40° C.) parts of the greenhouse, depending on their temperature requirements. The experiments were run for from 4 to 6 weeks. During this period the plants were tended and their reaction to the individual treatments was assessed. The application rate of the compounds examined is given in kg/ha of active ingredient. For assessment, the 0 to 100 scale was used, 0 denoting no damage or normal emergence, and 100 denoting no emergence or complete destruction of at least the visible plant parts.

II. Experiments in the open

The experiments were carried out on small plots in a loamy sand (pH 5 to 6) containing from 1 to 1.5% humus. Treatment was preemergence, and was effected either immediately after sowing or at the latest 3 days later. The crop plants were sown in rows. The weed flora was made up of widely varying species and was natural. The compounds were applied, as an emulsion or suspension in water, with the aid of a motor-driven plot spray. Where no rain fell, sprinkling was carried out to ensure germination and growth of crop plants and weeds. All the experiments were run for several weeks or months. During this period, assessments on the 0 to 100 scale were made at various intervals.

Results

The new compounds exhibit a high degree of herbicidal activity (Tables 2, 3, 4, 5 and 6). Compared with prior art active ingredients, they offer advantages either with regard to their action on unwanted plants or they are much better tolerated by crop plants.

The compounds according to the invention are selective herbicidal active ingredients for the control of unwanted plants in agricultural and horticultural crops and forestry. They may also be used for removing plant growth on non-cropland, e.g., as total weedkillers on railroads, parking lots and in industrial plants. They may further be used for controlling or eliminating the growth of unwanted woody plants in aggregate and other fruit, nuts and grapes. Examples of crop plants are as follows:

    ______________________________________                                         Botanical name     Common name                                                 ______________________________________                                         Allium cepa        onions                                                      Ananas comosus     pineapple                                                   Arachis hypogaea   peanuts (groundnuts)                                        Asparagus officinalis                                                                             asparagus                                                   Avena sativa       oats                                                        Beta vulgaris spp. altissima                                                                      sugarbeets                                                  Beta vulgaris spp. rapa                                                                           fodder beets                                                Beta vulgaris spp. esculenta                                                                      table beets, red beets                                      Brassica napus var. napus                                                                         rape                                                        Brassica napus var. napobrassica                                               Brassica napus var. rapa                                                                          turnips                                                     Brassica rapa var. silvestris                                                  Camellia sinensis  tea plants                                                  Carthamus tinctorius                                                                              safflower                                                   Carya illinoinensis                                                                               pecan trees                                                 Citrus limon       lemon                                                       Citrus maxima      grapefruit                                                  Citrus reticulata                                                              Citrus sinensis    orange trees                                                Coffea arabica (Coffea canephora,                                                                 coffee plants                                               Coffea liberica)                                                               Cucumis melo       melons                                                      Cucumis sativus    cucumber                                                    Cynodon dactylon   Bermudagrass in turf and                                                       lawns                                                       Daucus carota      carrots                                                     Elacis guineensis  oil palms                                                   Fragaria vesca     strawberries                                                Glycine max        soybeans                                                    Gossypium hirsutum cotton                                                      (Gossypium arboreum                                                            Gossypium herbaceum                                                            Gossypium vitifolium)                                                          Helianthus annuus  sunflowers                                                  Helianthus tuberosus                                                           Hevea brasiliensis rubber plants                                               Hordeum vulgare    barley                                                      Humulus lupulus    hops                                                        Ipomoea batatas    sweet potato                                                 Juglans regia     walnut trees                                                Lactuca sativa     lettuce                                                     Lens culinaris     lentils                                                     Linum usitatissimum                                                                               flax                                                        Lycopersicon lycopersicum                                                                         tomato                                                      Malus spp.         apple trees                                                 Manihot esculenta  cassava                                                     Medicago sativa    alfalfa (lucerne)                                           Mentha piperita    peppermint                                                  Musa spp.          banana plants                                               Nicotiana tabacum (N. rustica)                                                                    tobacco                                                     Olea europaea      olive trees                                                 Oryza sativa       rice                                                        Panicum miliaceum                                                              Phaseolus lunatus  limabeans                                                   Phaseolus mungo    mungbeans                                                   Phaseolus vulgaris snapbeans, green beans,                                                        dry beans                                                   Pennisetum glaucum                                                             Petroselinum crispum                                                                              parsley                                                     spp. tuberosum                                                                 Picea abies        Norway spruce                                               Abies alba         fir                                                         Pinus spp.         pine trees                                                  Pisum sativum      English peas                                                Prunus avium       cherry trees                                                Prunus domestica   plum trees                                                  Prunus dulcia      almond trees                                                Prunus persica     peach trees                                                 Pyrus communis     pear trees                                                  Ribes sylvestre    redcurrants                                                 Ribes uva-crispa                                                               Ricinus communis                                                               Saccharum officinarum                                                                             sugar cane                                                  Secale cereale     rye                                                         Sesamum indicum    Sesami                                                      Solanum tuberosum  Irish potatoes                                              Sorghum bicolor (s. vulgare)                                                                      sorghum                                                     Sorghum dochna                                                                 Spinacia oleracea  spinach                                                     Theobroma cacao    cacao plants                                                Trifolium pratense red clover                                                  Triticum aestivum  wheat                                                       Vaccinium corymbosum                                                                              blueberry                                                   Vaccinium vitis-idaea                                                                             cranberry                                                   Vicia faba         tick beans                                                  Vigna sinensis (V. unguiculata)                                                                   cow peas                                                    Vitis vinifera     grapes                                                      Zea mays           Indian corn, sweet corn,                                                       maize                                                       ______________________________________                                    

In the tables, pre- and postemergence use are documented. In addition to surface aplication, the agents may of course also be incorporated into the soil either before or after crop plants are sown, or after the crop plants have emerged.

Special applications such as post-directed or lay-by treatment are also possible. In this case, the spray is directed in such a manner that the leaves of sensitive crop plants are not touched; the agents are sprayed onto the soil beneath the crop plants, or the unwanted plants growing there.

In view of the wide variety of application methods, the agents according to the invention, or compositions containing them, may be used not only in the crop plants in the above tables, but also in a further large number of crop plants for eliminating unwanted plants. The application rates may vary from 0.1 to 15 kg/ha and more, depending on the object to be achieved.

                  TABLE 1                                                          ______________________________________                                         List of test plants                                                                           Abbreviation                                                    Botanical name in tables  Common name                                          ______________________________________                                         Abutilon theophrasti                                                                          Abutilon theo.                                                                            velvet leaf                                          Alopecurus myosuroides                                                                        Alepec. myos.                                                                             slender foxtail                                      Amaranthus retroflexus                                                                        Amar. retr.                                                                               redroot pigweed                                      Avena fatua    Avena fat. wild oats                                            Chenopodium album                                                                             Chenop. alb.                                                                              lambsquarters                                                                  (goosefoot)                                          Chrysanthemum segetum                                                                         Chrys. seg.                                                                               corn marigold                                        Ipomoea spp.   Ipom. spp. morningglory                                         Datura stramonium                                                                             Datura stram.                                                                             jimsonweed                                           Echinochloa crus galli                                                                        Echin. c.g.                                                                               barnyardgrass                                        Euphorbia geniculata                                                                          Euph. gen. South American                                                                 member of                                                                      the spurge family                                    Galium aparine Galium apar.                                                                              catchweed bedstraw                                   Glycine max    Glyc. max  soybeans                                             Gossypoum hirsutum                                                                            Gossyp. hirs.                                                                             cotton                                               Matricaria spp.                                                                               Matric. spp.                                                                              chamomile                                            Oryza sativa   Oryza sat. rice                                                 Polygonum persicaria                                                                          Polyg. pers.                                                                              ladysthumb                                           Portulaca oleracea                                                                            Port. oler.                                                                               purslane                                             Sida spinosa   Sida pin.  teaweed (prickly sida)                               Sinapis alba     --       white mustard                                        Solanum nigrum Solan. nigr.                                                                              black nightshade                                     Stellaria media                                                                                 --       chickweed                                            Veronica spp.    --       speedwell                                            ______________________________________                                    

                                      TABLE 2                                      __________________________________________________________________________     Herbicidal action and tolerance of active ingredients by crop plants;          preemergence application in the greenhouse                                      ##STR138##                                                                    __________________________________________________________________________     Com-                         Test plants and % damage                          pound                        Glyc.                                                                              Gossyp.                                                                            Oryza                                                                              Abutilon                                                                             Alopec.                                                                             Amaranth.                                                                           Chrys.                no. R   R.sup.1                                                                            R.sup.2    R.sup.3                                                                          kg/ha                                                                               max                                                                               hirs.                                                                              sat.                                                                               theo. myos.                                                                               retr.                                                                               seg.                  __________________________________________________________________________     1   OCH.sub.3                                                                          OCH.sub.3                                                                          F          F 1.0  0  --  10  --    --   98    90                   2   OCH.sub.3                                                                          OCH.sub.3                                                                          CHF.sub.2  H 0.5 10  --  --  100   70   30   --                                             1.0 10  --  --  100   100  100  --                    3   OCH.sub.3                                                                          OCH.sub.3                                                                          OCF.sub. 2CHFCF.sub.3                                                                     H 0.5 15   0  --  100   70   100  --                                             1.0 55   0  --  100   98   100  --                                                             Portulac.       Euph. gen.            4   OCH.sub.3                                                                          OCH.sub.3                                                                          OCHF.sub.2 H 0.5 --  10  --  100   90   40   100                                            1.0 --  20  --  100   95   75   100                                                            Abutilon                              5   OCH.sub.3                                                                          OCH.sub.3                                                                          OCF.sub.2CHF.sub.2                                                                        H 0.5 --   0  10  100   92   98   100                                            1.0 --   5  20  100   95   98   100                                            2.0 --  10  60  --    95   95   100                   A   OCH.sub.3                                                                          OCH.sub.3                                                                          H          H 0.5 15  40  20   90   52   78    95                   prior                    1.0 15  55  20  100   72   93   100                   art                                                                            __________________________________________________________________________     Com-                         Test plants and % damage                          pound                        Datura                                                                             Ipom.                                                                              Matric                                                                             Sida  Sinapsis                                                                            Solan.                                                                              Stellaria             no. R   R.sup.1                                                                            R.sup.2    R.sup.3                                                                          kg/ha                                                                               stram.                                                                            spp.                                                                               spp.                                                                               spin. alba nigr.                                                                               media                 __________________________________________________________________________     1   OCH.sub.3                                                                          OCH.sub.3                                                                          F          F 1.0 80  --  100 70    90   98   --                    2   OCH.sub.3                                                                          OCH.sub.3                                                                          CHF.sub.2  H 0.5 95  100 100 100   --   100  100                                            1.0 95  100 100 100   --   100  100                   3   OCH.sub.3                                                                          OCH.sub.3                                                                          OCF.sub.2CHFCF.sub.3                                                                      H 0.5 75  100 100 100   --   100  100                                            1.0 95  100 100 100   --   100  100                   4   OCH.sub.3                                                                          OCH.sub.3                                                                          OCHF.sub.2 H 0.5 --   65 100 70    --   45    90                                            1.0 --   65 100 95    --   70   100                                                                  Echin.                          5   OCH.sub.3                                                                          OCH.sub.3                                                                          OCF.sub.2CHF.sub.2                                                                        H 0.5 95   85 100 98    55   98   100                                            1.0 95   90 100 98    80   98   100                                            2.0 --  100 100 100   95   95   100                   A   OCH.sub.3                                                                          OCH.sub.3                                                                          H          H 0.5 89   66 100 53    98   92    94                   prior                    1.0 94  100 100 69    98   98    98                   art                                                                            __________________________________________________________________________      0 = no damage                                                                  100 = plants destroyed                                                   

                                      TABLE 3                                      __________________________________________________________________________     Herbicidal action and tolerance of new active ingredients                      by crop plants; preemergence application in the open                            ##STR139##                                                                                                   Test plants and % damage                        Compound                       Gossyp.                                                                            Amar.                                                                              Chenop.                                                                             Echin.                                                                             Polyg.                         no.   R     R.sup.1                                                                            R.sup.2  R.sup.3                                                                          kg/ha                                                                               hirs.                                                                             retr.                                                                              alb. c.g.                                                                               pers.                          __________________________________________________________________________     5     OCH.sub.3                                                                            OCH.sub.3                                                                          OCF.sub.2CHF.sub.2                                                                      H 1.0  1   67 84   51  30                                                        2.0 11   93 95   78  70                             A     OCH.sub.3                                                                            OCH.sub.3                                                                          H        H 1.0 20   90 92   37  10                             prior art                  2.0 55  100 99   68  56                             B prior art                                                                           ##STR140##                                                                          Cl  OCF.sub.2CHF.sub.2                                                                      H 1.0 2.0                                                                            19 36                                                                               72 35 60                                                                               34 58                                                                               2 12                          __________________________________________________________________________      0 = no damage                                                                  100 = nonemergence, or plants destroyed                                  

                                      TABLE 4                                      __________________________________________________________________________     Herbicidal action of new active ingredients; postemergence application         in the greenhouse                                                               ##STR141##                                                                                                    Test plants and % damage                       Compound                        Avena                                                                              Echin.                                                                             Amar.                                                                              Euph.                                                                              Galium                                                                             Port.                                                                             Sida                                                                              Veronica             no.   R   R.sup.1                                                                            R.sup.2     R.sup.3                                                                          kg/ha                                                                               fat.                                                                              c.g.                                                                               retr.                                                                              gen.                                                                               agar                                                                               oler.                                                                             spin.                                                                             spp.                 __________________________________________________________________________     5     OCH.sub.3                                                                          OCH.sub.3                                                                          OCF.sub.2CHF.sub.2                                                                         H 1.0 100 98  100 100 95  100                                                                               100                                                                               100                  3     OCH.sub.3                                                                          OCH.sub.3                                                                          OCF.sub.2CHFCF.sub.3                                                                       H 1.0 --  100 100 --  90  -- 100                                                                               --                   4     OCH.sub.3                                                                          OCH.sub.3                                                                          OCHF.sub.2  H 1.0 100 85   90 20  --  100                                                                               100                                                                               100                  2     OCH.sub.3                                                                          OCH.sub.3                                                                          CHF.sub.2   H 1.0 --  100 --  --  80  --  60                                                                               --                   6     OCH.sub.3                                                                          OCH.sub.3                                                                          SCF.sub.3   H 1.0 --  80  --  --  98  -- -- --                   A     OCH.sub.3                                                                          OCH.sub.3                                                                          H           H 1.0  80 70   75 22  60  100                                                                                80                                                                               100                  prior                                                                          art                                                                            __________________________________________________________________________      0 = no damage                                                                  100 = plants destroyed                                                   

                                      TABLE 5                                      __________________________________________________________________________     Selective herbicidal action of the active ingredients;                         preemergence application in the greenhouse                                      ##STR142##                                                                                                  Test plants and % damage                                                       Gossyp-     Eu-                                                                ium Abu-                                                                               Echi-                                                                              phor-  Portu-                                                                             Ses-                      Com-                          hirsut-                                                                            tilon                                                                              nochloa                                                                            bia Ipo-                                                                              laca                                                                               bania  Sida               pound                      kg/                                                                               um  theo-                                                                              crus                                                                               genic-                                                                             moea                                                                              oler-                                                                              exal-                                                                             Setaria                                                                            spi-               no  R    R.sub.1                                                                             R.sub.2    R.sub.3                                                                          ha cotton                                                                              phrasti                                                                           galli                                                                              ulata                                                                              spp.                                                                              acea                                                                               tata                                                                              faberii                                                                            nosa               __________________________________________________________________________     2   OCH.sub.3                                                                           OCH.sub.3                                                                           CHF.sub.2  H 0.25                                                                               0  --  85  100 75 89  -- 70   95                                           0.5                                                                               10   92 85  --  98 89  72 98  100                3   OCH.sub.3                                                                           OCH.sub.3                                                                           OCF.sub.2CHFCF.sub.3                                                                      H 0.25                                                                               3   88 53  100 72 89  50 65   90                                           0.5                                                                                3  100 72  100 98 94  87 75  100                5   OCH.sub.3                                                                           OCH.sub.3                                                                           OCF.sub.2CHF.sub.2                                                                        H 0.25                                                                              15  100 92   98 75 90  65 85  100                6   OCH.sub.3                                                                           OCH.sub.3                                                                           SCF.sub.3  H 0.5                                                                               10  100 79  100 100                                                                               92  90 100 100                C   OCH.sub.3                                                                           OCH.sub.3                                                                           CF.sub.3   H 0.25                                                                              15  100 69   68 80 85  50 70  100                prior                                                                          art                                                                            __________________________________________________________________________

                                      TABLE 6                                      __________________________________________________________________________     Herbicidal action of the active ingredients; postemergence                     application in the greenhouse                                                   ##STR143##                                                                                                   Test plants and % damage                        Compound                       Centaurea                                                                            Echinochloa                                                                          Ipomoea                                                                             Lolium                         no.   R    R.sub.1                                                                             R.sub.2    R.sub.3                                                                             cyanus                                                                              crus galli                                                                           spp. multiflorum                    __________________________________________________________________________     7     OCH.sub.3                                                                           OCH.sub.3                                                                           OCF.sub.2CHFCl                                                                            H 3.0                                                                              100   100   100  100                            8     OCH.sub.3                                                                           OCH.sub.3                                                                           OCF.sub.2CHFBr                                                                            H 3.0                                                                              100   100   100  100                            9     OC.sub.2 H.sub.5                                                                    OC.sub.2 H.sub.5                                                                    OCF.sub.2CHF.sub.2                                                                        H 3.0                                                                              --    100    70  100                            10    OCH.sub.3                                                                           OCH.sub.3                                                                           OCF.sub.3  H 3.0                                                                              100   100   100  100                            __________________________________________________________________________

EXAMPLE 4

90 parts by weight of compound 1 is mixed with 10 parts by weight of N-methyl-α-pyrrolidone. A mixture is obtained which is suitable for application in the form of very fine drops.

EXAMPLE 5

20 parts by weight of compound 2 is dissolved in a mixture consisting of 80 parts by weight of xylene, 10 parts by weight of the adduct of 8 to 10 moles of ethylene oxide to 1 mole of oleic acid-N-monoethanolamide, 5 parts by weight of the calcium salt of dodecylbenzenesulfonic acid, and 5 parts by weight of the adduct of 40 moles of ethylene oxide to 1 mole of castor oil. By pouring the solution into 100,000 parts by weight of water and uniformly distributing it therein, an aqueous dispersion is obtained containing 0.02% by weight of the active ingredient.

EXAMPLE 6

20 parts by weight of compound 3 is dissolved in a mixture consisting of 40 parts by weight of cyclohexanone, 30 parts by weight of isobutanol, 20 parts by weight of the adduct of 7 moles of ethylene oxide to 1 mole of isooctylphenol, and 10 parts by weight of the adduct of 40 moles of ethylene oxide to 1 mole of castor oil. By pouring the solution into 100,000 parts by weight of water and finely distributing it therein, an aqueous dispersion is obtained containing 0.02% by weight of the active ingredient.

EXAMPLE 7

20 parts by weight of compound 1 is dissolved in a mixture consisting of 25 parts by weight of cyclohexanol, 65 parts by weight of a mineral oil fraction having a boiling point between 210° and 280° C., and 10 parts by weight of the adduct of 40 moles of ethylene oxide to 1 mole of castor oil. By pouring the solution into 100,000 parts by weight of water and uniformly distributing it therein, an aqueous dispersion is obtained containing 0.02% by weight of the active ingredient.

EXAMPLE 8

20 parts by weight of compound 2 is well mixed with 3 parts by weight of the sodium salt of diisobutylnaphthalene-α-sulfonic acid, 17 parts by weight of the sodium salt of a lignin-sulfonic acid obtained from a sulfite waste liquor, and 60 parts by weight of powdered silica gel, and triturated in a hammer mill. By uniformly distributing the mixture in 20,000 parts by weight of water, a spray liquor is obtained containing 0.1% by weight of the active ingredient.

EXAMPLE 9

3 parts by weight of compound 3 is intimately mixed with 97 parts by weight of particulate kaolin. A dust is obtained containing 3% by weight of the active ingredient.

EXAMPLE 10

30 parts by weight of compound 4 is intimately mixed with a mixture consisting of 92 parts by weight of powdered silica gel and 8 parts by weight of paraffin oil which has been sprayed onto the surface of this silica gel. A formulation of the active ingredient is obtained having good adherence.

EXAMPLE 11

40 parts by weight of compound 1 is intimately mixed with 10 parts of the sodium salt of a phenolsulfonic acid-urea-formaldehyde condensate, 2 parts of silica gel and 48 parts of water. Dilution in 100,000 parts by weight of water gives an aqueous dispersion containing 0.04 wt % of active ingredient.

EXAMPLE 12

20 parts of compound 2 is intimately mixed with 2 parts of the calcium salt of dodecylbenzenesulfonic acid, 8 parts of a fatty alcohol polyglycol ether, 2 parts of the sodium salt of a phenolsulfonic acid-urea-formaldehyde condensate and 68 parts of a paraffinic mineral oil. A stable oily dispersion is obtained. 

We claim:
 1. A substituted pyridazone selected from the group consisting of 1-(3-tetrafluoroethoxyphenyl)-4,5-dimethoxypyridazone-6 and 1-(3-monobromotrifluoroethoxyphenyl)-4,5-dimethoxypyridazone.-6
 2. A process for combating the growth of unwanted plants wherein the soil or the plants are treated with a substituted pyridazone selected from the group consisting of 1-(3-tetrafluoroethoxyphenyl)-4,5-dimethoxypyridazone-6 and 1-(3-monobromotrifluoroethoxyphenyl)-4,5-dimethoxypyridazone-6. 